Cause & Control of Prolapse
By Miller Hatcheries
One of the most frustrating things about prolapse is that it takes its toll form the best birds in the house - - those in lay. Now that marek's is out of fashion, prolapse can account for a very substantial proportion of laying house mortality. The problem frequently fades in retrospect, however, because the flock that passes through the "prolapse syndrome" usually goes on to a good performance record once it settles down. This may account in part for the fact that comparatively little attention is given to the condition, and to its prevention and cure.
Prolapse, in lay language, is the eversion of the oviduct and rectal organs through the vent to the extent that they don't retract again. It is a condition that almost invariable results in death. Even if the prolapse is discovered in time, and the organs replaced in position, the bird will seldom make a recovery. What happens more often than not, is that she quickly becomes a "pickout".
The foundations for prolapse are laid down in the rearing stage, and faulty feeding and light programs during that period contribute to the condition.
Causes of Prolapse
The overly fat pullet at point of lay is a prime target for prolapse. The use of a rearing program that allows her to eat ad lib, when she should be slightly restricted, or one that encourages over consumption of protein is asking for trouble because of the association of high levels of protein and egg size.
Equally at fault is the mistimed light program that brings immature pullets to point of lay before the oviduct muscles have developed elasticity and strength. Worse still, perhaps, is the too-sudden increase in day length that results in erratic ovulation - - many double-yolked eggs which, by size alone, can cause prolapse or blowouts.
The laying of an egg is invariable accompanied by some eversion of the oviduct. This is out. The tissues around the vent are wonderfully elastic, even in young pullets at the point of lay and after the egg is produced, and everything returns to its original position with no harm done. Nor harm done, that is, if we haven't set the stage for trouble by faulty feeding and lighting.
If we have allowed the bird to build up too much abdominal fat, this reduces the elasticity of the oviduct and vent muscles, often to the point where they cannot return to their normal position - - hence, prolapse, or blowout. If the light program has encouraged too early egg production or oversized eggs, before the muscles can cope with the situation, we find ourselves with the same problem.
Other causes of prolapse
The entire blame for prolapse cannot be placed at the door of light and
feed. There are other causes: over crowding, enteritis, hormone imbalance,
and one of the most common - - physical damage inflicted on the oviduct
tissues. In this latter case, picking at the slightly exposed oviduct, as it
is laid, can sometimes inflict sufficient bruising and irritation upon the
tissues that they prolapse after the next egg is produced.
Good management is the key to preventing prolapse, and good management, promptly applied, can help to minimize the seriousness of blowouts if the "syndrome" begins to appear. The incidence of "pickouts", for example, can be drastically reduced by attention to two relatively simple details - - beak retrimming and light intensity.
A good percentage of the mortality that is generally ascribed to prolapse is not true prolapse, as we know the term. It is actually cannibalism triggered by pullets picking at the slightly inverted vent of another during egg laying, until she becomes a victim of pickout. And it can generally be either prevented or brought under control by reducing the intensity of light to 1.5 foot-candles at feed trough level, and or by retrimming the beaks of those pullets that require this treatment at housing.
Checking the pullet for enteritis, worms or any other health hazard that could cause prolapse.
So, too, will a watchful eye on flock density. C. E. Ostrander, of Cornell University's poultry husbandry department, reports on a cage density test using no beak trimmed birds. No cannibalism showed in two and three-bird cages, but it did occur in those housing four and five birds.
Occasionally, a producer will pin his prolapse problems onto the strain of bird he is handling at the moment. Actually, of all competitive stocks on the market today, none has the prolapse tendency as a recognizable fault; breeders have long ago eliminated families showing the characteristic.
Four key details in growing pullets
In the prevention of prolapse, the pullet replacement grower should concentrate on four key details.
Control of Prolapse
A feeding program that brings the pullet to point of lay in lean
condition with a well-developed frame - - and no excess fat.
A light program that (a) restricts maturity until the pullet is
physically ready for egg production, (b) avoids setting the stage for
erratic ovulation - - mainly manifest in doubled-yolked eggs.
A correctly done beak trimming job, one good enough as to require only
"touching up" at housing time.
Check bird health, particularly with regard to enteritis and other
In the control of prolapse, the laying house operator has four important areas to watch.
He should make sure that the incoming pullets are properly beak
He should be alert to his feeding program, controlling any tendency for
the flock to overeat and put on excessive weight.
He should be able to quickly reduce light intensity at feed and water
level to one foot-candle, if necessary.
4. He should avoid too heavy
Keep in mind that outbreaks of prolapse and pickouts are nearly always triggered by something we mismanaged somewhere back along the line. These problems can be prevented and they can be controlled.